Epidemiological studies have identified alcohol as an important risk factor for HIV-1 infection. Alcohol exposure increases HIV-1 replication and accelerates clinical progression to AIDS. Our long-range goal is total eradication of T cells that harbor integrated HIV-1 during the clinically latent phase of the disease. The objective of this application is to better understand the mechanism of alcohol in the reactivation of viral replication in latent T lymphocytes. Based on the Preliminary Results, our hypothesis is that alcohol/alpha-CD3 co-stimulation initiates productive viral replication in latent T lymphocytes infected with HIV-1. The Specific Aims of this application are as follows: (1) to determine the mechanism of alcohol-induced reactivation of latent CD4+ T cells infected with HIV-1; (2) to elucidate the second messenger signaling involved in latent viral replication induced by alcohol; (3) to study the effect of alcohol/alpha-CD3 on transcription factor NF-kappaB-mediated HIV-1 long terminal repeat (LTR) transcription; and (4) to examine the role of alcohol/alpha-CD3 on cytokine-dependent and NF-kappaB-independent induction of latent HIV-1 replication. We propose a biochemical approach to explore the ability of alcohol to modulate T cell receptor (TCR)/CD3-mediated T-lymphocyte activation utilizing purified CD4+ T cells derived from peripheral blood lymphocytes (PBLs). This is based on our preliminary work, which demonstrated that alcohol and alpha-CD3 co-stimulation enhances viral replication in latently infected PBLs. At the conclusion of this project, we expect to demonstrate that alcohol increases TCR/CD3 mediated induction of latent virus in CD4+ T cells. The significance of this study lies in its important clinical implications. Excessive alcohol consumption may hasten the progression of latent, asymptomatic infection to AIDS. In addition, the proposed study is expected to reveal novel target sites for antiretroviral treatment.